ndb_desc provides a detailed description of one or more NDB tables.

Usage

ndb_desc -c connect_string tbl_name -d db_name [-p]      ndb_desc -c connect_string index_name -d db_name -t tbl_name

Sample Output

MySQL table creation and population statements:

USE test;CREATE TABLE fish (    id INT(11) NOT NULL AUTO_INCREMENT,    name VARCHAR(20) NOT NULL,    length_mm INT(11) NOT NULL,    weight_gm INT(11) NOT NULL,    PRIMARY KEY pk (id),    UNIQUE KEY uk (name)) ENGINE=NDB;INSERT INTO fish VALUES    ('','guppy', 35, 2), ('','tuna', 2500, 150000),    ('','shark', 3000, 110000), ('','manta ray', 1500, 50000),    ('','grouper', 900, 125000), ('','puffer', 250, 2500);

Output from ndb_desc:

shell> ./ndb_desc -c localhost fish -d test -p-- fish --Version: 2Fragment type: 9K Value: 6Min load factor: 78Max load factor: 80Temporary table: noNumber of attributes: 4Number of primary keys: 1Length of frm data: 311Row Checksum: 1Row GCI: 1SingleUserMode: 0ForceVarPart: 1FragmentCount: 2TableStatus: Retrieved-- Attributes --id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCRname Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORYlength_mm Int NOT NULL AT=FIXED ST=MEMORYweight_gm Int NOT NULL AT=FIXED ST=MEMORY-- Indexes --PRIMARY KEY(id) - UniqueHashIndexPRIMARY(id) - OrderedIndexuk$unique(name) - UniqueHashIndexuk(name) - OrderedIndex-- Per partition info --Partition  Row count  Commit count  Frag fixed memory ...0          2          2             32768             ...1          4          4             32768             ...... Frag varsized memory  Extent_space  Free extent_space... 32768                 0             0... 32768                 0             0NDBT_ProgramExit: 0 - OK

Information about multiple tables can be obtained in a single invocation of ndb_desc by using their names, separated by spaces. All of the tables must be in the same database.

You can obtain additional information about a specific index using the --table (short form: -t) option supplying the name of the index as the first argument to ndb_desc, as shown here:

shell> ./ndb_desc uk -d test -t fish-- uk --Version: 3Base table: fishNumber of attributes: 1Logging: 0Index type: OrderedIndexIndex status: Retrieved-- Attributes --name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY-- IndexTable 10/uk --Version: 3Fragment type: FragUndefinedK Value: 6Min load factor: 78Max load factor: 80Temporary table: yesNumber of attributes: 2Number of primary keys: 1Length of frm data: 0Row Checksum: 1Row GCI: 1SingleUserMode: 2ForceVarPart: 0FragmentCount: 4ExtraRowGciBits: 0ExtraRowAuthorBits: 0TableStatus: Retrieved-- Attributes --name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORYNDB$TNODE Unsigned [64] PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY-- Indexes -- PRIMARY KEY(NDB$TNODE) - UniqueHashIndexNDBT_ProgramExit: 0 - OK

When an index is specified in this way, the --extra-partition-info and --extra-node-info options have no effect.

The Version column in the output contains the table's schema object version. For information about interpreting this value, see NDB Schema Object Versions.

The Extent_space and Free extent_space columns are applicable only to NDB tables having columns on disk; for tables having only in-memory columns, these columns always contain the value 0.

To illustrate their use, we modify the previous example. First, we must create the necessary Disk Data objects, as shown here:

CREATE LOGFILE GROUP lg_1    ADD UNDOFILE 'undo_1.log'    INITIAL_SIZE 16M    UNDO_BUFFER_SIZE 2M    ENGINE NDB;ALTER LOGFILE GROUP lg_1    ADD UNDOFILE 'undo_2.log'    INITIAL_SIZE 12M    ENGINE NDB;CREATE TABLESPACE ts_1    ADD DATAFILE 'data_1.dat'    USE LOGFILE GROUP lg_1    INITIAL_SIZE 32M    ENGINE NDB;ALTER TABLESPACE ts_1    ADD DATAFILE 'data_2.dat'    INITIAL_SIZE 48M    ENGINE NDB;

(For more information on the statements just shown and the objects created by them, see Section 17.5.12.1, "MySQL Cluster Disk Data Objects", as well as Section 13.1.14, "CREATE LOGFILE GROUP Syntax", and Section 13.1.18, "CREATE TABLESPACE Syntax".)

Now we can create and populate a version of the fish table that stores 2 of its columns on disk (deleting the previous version of the table first, if it already exists):

CREATE TABLE fish (    id INT(11) NOT NULL AUTO_INCREMENT,    name VARCHAR(20) NOT NULL,    length_mm INT(11) NOT NULL,    weight_gm INT(11) NOT NULL,    PRIMARY KEY pk (id),    UNIQUE KEY uk (name)) TABLESPACE ts_1 STORAGE DISK ENGINE=NDB;INSERT INTO fish VALUES    ('','guppy', 35, 2), ('','tuna', 2500, 150000),    ('','shark', 3000, 110000), ('','manta ray', 1500, 50000),    ('','grouper', 900, 125000), ('','puffer', 250, 2500);

When run against this version of the table, ndb_desc displays the following output:

shell> ./ndb_desc -c localhost fish -d test -p-- fish --Version: 3Fragment type: 9K Value: 6Min load factor: 78Max load factor: 80Temporary table: noNumber of attributes: 4Number of primary keys: 1Length of frm data: 321Row Checksum: 1Row GCI: 1SingleUserMode: 0ForceVarPart: 1FragmentCount: 2TableStatus: Retrieved-- Attributes --id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCRname Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORYlength_mm Int NOT NULL AT=FIXED ST=DISKweight_gm Int NOT NULL AT=FIXED ST=DISK-- Indexes --PRIMARY KEY(id) - UniqueHashIndexPRIMARY(id) - OrderedIndexuk$unique(name) - UniqueHashIndexuk(name) - OrderedIndex-- Per partition info --Partition  Row count  Commit count  Frag fixed memory ...0          2          2             32768             ...1          4          4             32768             ...... Frag varsized memory  Extent_space  Free extent_space... 32768                 0             0... 32768                 0             0NDBT_ProgramExit: 0 - OK

This means that 1048576 bytes are allocated from the tablespace for this table on each partition, of which 1044440 bytes remain free for additional storage. In other words, 1048576 - 1044440 = 4136 bytes per partition is currently being used to store the data from this table's disk-based columns. The number of bytes shown as Free extent_space is available for storing on-disk column data from the fish table only; for this reason, it is not visible when selecting from the INFORMATION_SCHEMA.FILES table.

The following table includes options that are specific to ndb_desc. Additional descriptions follow the table. For options common to most MySQL Cluster programs (including ndb_desc), see Section 17.4.25, "Options Common to MySQL Cluster Programs — Options Common to MySQL Cluster Programs".